1. Field of the Invention
The present invention relates to a communication apparatus and a method of controlling the same, as well as a storage medium, and more particularly to a communication apparatus that selectively uses codecs, a method of controlling the communication apparatus, and a storage medium.
2. Description of the Related Art
In recent years, attention has been being given to IP-FAX which transmits and receives FAX using an IP network. The IP-FAX is also mentioned as one of services provided by the NGN network which is the public IP network of NTT (registered trademark).
As is apparent from the fact that communication speed of the NGN network is one Mbps maximum, IP-FAX communication speed is high, so that it is possible to transmit or receive an image in shorter time than in facsimile communication using a conventional analog line.
Further, it is expected that the IP-FAX will be used for high-resolution facsimile transmission/reception and color facsimile transmission/reception in which the amount of data to be transmitted is large, by making the most of the high-speed transmission capability of the IP-FAX.
Further, since the IP network is used, it is possible to easily increase the number of simultaneous communications without adding a telephone line or modem hardware which is necessary for the conventional analog network, so that multi-session is enabled.
Note that the conventional analog facsimile machine can be also connected to a public IP network via a T.38 gateway (GW). Although detailed description is omitted because the technique is conventionally known, IP-FAX machines establish call connection therebetween using SIP (Session Initiation Protocol) and perform data communication using the T.38 protocol.
In conjunction with this, a T.38 gateway converts the SIP call connection to an analog telephone call connection and the T.38 protocol to the T.30 protocol on a real-time basis, to thereby enable communication between an IP-FAX machine and an analog facsimile machine (see e.g. Japanese Patent Laid-Open Publication NO. 2003-92671).
In a case where an IP-FAX machine communicates with an analog facsimile machine via a T.38 gateway, the communication speed of the IP-FAX machine cannot be increased to a speed higher than 14400 bps set as the maximum communication speed of a V.17 analog facsimile machine.
The communication between conventional analog facsimile machines is performed at a low communication speed as mentioned above, so that a software codec suffices to perform image encoding and decoding.
The NGN network guarantees a bandwith of 1 Mbps at maximum, but e.g. in a case where encoding and decoding is performed using the software codec, the processing speed is too slow to make the most of the performance of the public IP network.
Further, since the NGN network employs time-based charging, slower communication speed forces users to pay more money.
For this reason, it is desirable to use a hardware codec for image coding and decoding. However, it is disadvantageous in terms of costs to equip an IP-FAX machine with dedicated hardware codecs corresponding in number to communication lines for multi-session. Therefore, hardware codecs cannot be used for all communications.
On the other hand, in a case where an IP-FAX machine communicates with an analog facsimile machine via a T.38 gateway, as mentioned hereinabove, communication speed cannot exceed the maximum communication speed of 14400 bps of the analog facsimile machine, so that a software codec suffices to process data.
Further, even in communication between IP-FAX machines, when not the public IP network but a local IP network is used, no charge is imposed on the communication even if the communication takes some long time. Therefore, even if the communication speed is reduced to some extent due to the use of a software codec, there is no fear that the communication charge will increase.